Re: [RESEND PATCH v2 2/4] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2016-06-21 02:00:15
Also in:
linux-pci, lkml
On Thu, Jun 02, 2016 at 01:46:49PM +0800, Yongji Xie wrote:
Now we use the IORESOURCE_STARTALIGN to identify bridge resources in __assign_resources_sorted(). That's quite fragile. We can't make sure that the PCI devices' resources will not use IORESOURCE_STARTALIGN any more.
Can you explain this a little more? I don't quite understand the problem. Maybe you can give an example of the problem?
quoted hunk ↗ jump to hunk
In this patch, we try to use a more robust way to identify bridge resources. Signed-off-by: Yongji Xie <redacted> --- drivers/pci/setup-bus.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 55641a3..216ddbc 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c@@ -390,6 +390,7 @@ static void __assign_resources_sorted(struct list_head *head, struct pci_dev_resource *dev_res, *tmp_res, *dev_res2; unsigned long fail_type; resource_size_t add_align, align; + int index; /* Check if optional add_size is there */ if (!realloc_head || list_empty(realloc_head))@@ -410,11 +411,13 @@ static void __assign_resources_sorted(struct list_head *head, /* * There are two kinds of additional resources in the list: - * 1. bridge resource -- IORESOURCE_STARTALIGN - * 2. SR-IOV resource -- IORESOURCE_SIZEALIGN + * 1. bridge resource + * 2. SR-IOV resource * Here just fix the additional alignment for bridge */ - if (!(dev_res->res->flags & IORESOURCE_STARTALIGN)) + index = dev_res->res - dev_res->dev->resource; + if (index < PCI_BRIDGE_RESOURCES || + index > PCI_BRIDGE_RESOURCE_END)
I think the code looks OK; at least, it seems to match the comment. I'd just like to understand the problem a little better.
continue; add_align = get_res_add_align(realloc_head, dev_res->res); -- 1.7.9.5